docs: def get_datetime_properties(self, recursive=True):
          """
          Returns a dict of property.path and property.
  
          :param recursive the name of the property
          :returns a dict
  
          """
          res = {}
          for name, field in self.properties.items():
              if isinstance(field, DateField):
                  res[name] = field
              elif recursive and isinstance(field, ObjectField):
                  for n, f in field.get_datetime_properties(recursive=recursive):
                      res[name + "." + n] = f
          return res